After you file

When my Mom called the IRS, the man she was speaking to was not helpful.  He didn't seem to understand the issue and after a couple of hours of her being on the phone with him, he said he wasn't certain she could file an amended form and referred her to the IRS.gov website -- that was certainly not helpful.  I'm fine with helping her file  her amended tax form, however, because her error caused most of the calculations in the form to be incorrect, I just need to know if I have to change the original submitted tax form to match the adjustment the IRS made first.  I hope this is clear enough.  Thank you